Hi  and a happy holliday Since linux is open source its free to be developed by anyone. So lets say ubuntu or debian  are two very popular versions of linux  now somebody comes along and wants to develop a new version. He  takes the ubuntu core operating system and adds a different desk top changes design  a different  look for the desktop and names it something else this is how new versions of linux are born .There are many versions that run on top of ubuntu or debian core systems. Matter a fact there is the off spin of ubuntu its the very popular  linux mint it is a version of ubuntu. I  feel mint is the best version of the ubuntu core .There are new releases all the time im going to give you the link to distro watch here you can find all the new releases .Here these two i will mention I tried them pre tested them.Ultimate os is a big full featured desktop pretty nice system. And tails is a debian based system tiny by comparison to most linux systems in size but that  tails os is a pretty cool thing it comes with Tor encrypted browser .You can even access the dark net with it  runs off a usb stick as a live os put the flash usb stick in your computer change settings to first boot off usb before the HD  restart your computer with the flash drive in tails should boot off the usb stick .With tails or any nice thing about linux you can run it just off live linux cd of flash drive hard to try it out before you install it no drive needed matter fact i had a computer the hard drive failed. I threw a linux cd in and surfed the web a week till the new drive came in the mail a week later never missed a beat of course you cant store files or download while running on a cd until you install it on your hard drive. Has every thing check both out at distro watch